A
sheet of molten rock roughly 10 miles thick spreads underneath
much of the American Southwest, some 250 miles below Tucson. From
the surface, you can't see it, smell it or feel it.But
Arizona geophysicists Daniel Toffelmier and James Tyburczy detected
the molten layer with a comparatively new and overlooked technique
for exploring deep within Earth that uses magnetic eruptions on
the sun.

For
Centuries, Man Has Yearned to Understand the Power of the Sun.
Now Area Scientists Are Working to Harness It.

It is
a commonplace, fairly average, class-G star -- not as hot as the
O- or B-class stars such as 10 Lacertra or Rigel, nor as cold
as the class-M supergiant Antares. But this star can affect the
navigation of homing pigeons and the precision of oil drillers.
Its mystery induced the ancients to cut out human hearts in sacrifice.
And its light makes the daily 93 million-mile trip to Earth in
about eight minutes. Scientists across Washington are trying to
simulate it, harness it and scrutinize it. Beachgoers bathe in
it. By August -- or maybe this afternoon -- we'll be cursing it.
And at 1:06 p.m. Thursday, its orientation in the sky officially
begins summer.